Protective apparatus



Feb. 17, 1 c. L. WETZEL PROTECTIVE APPARATUS Filed Sept. 30, 1926 mm/ CyJe z. Wefze/ by Patented Feb. 17, 1931 UNITED STATES PATENT oFFi'cE- CLYDE LEIGH WETZEL, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEVJ YORK PROTECTIVE APPARATUS Application filed September 30, 1926. Serial No. 138,601.

In accordance with the general features thereof, one embodiment of the invention contemplates the provision of protective apparatus for telephone exchanges and the like which includes a fuse mounting or block adapted for detachable association with a.

" supporting rack to electrically connect conductor elements carried by the rack, these ele ments forming terminals for switchboard circuits. Each fuse block comprises an insulating mounting or block having a terminal spring mounted on the upper and lower surfaces thereof and a fuse wire connecting the springs. The fuse wire is retained under tension and the upper spring is arranged to fly upwardly upon the parting of the fuse wire, thereby changing the positions of a bent or indicator portion of the upper spring with respect to the block to visibly indicate the ){LftlCLlltll fuse which has been parted and contemporaneously closing a general alarm circuit. The fuse blocks may be readily inserted and yieldingly held within the supporting racks and may be conveniently withdrawn therefrom for purposes of repair or replacement.

These and other obj ects will be more apparent from the following detailed description and the accompanying drawing, wherein Fig. 1 is a fragmentary front elevational view of a panel comprising a plurality of racks supporting protective devices repre senting one embodiment of the invention;

Fig. 2 is a horizontal, sectional view of the panel shown in Fig. l with certain portions of av rack broken away toexpose parts otherwise hidden; f

Fig. 3 is a, transverse, vertical, sectional view taken onl the linei 3f 3 o'f Fig. 2and showing sclielnat cnilly i an electrical alarm 9 circuit, and

Fig. 4 is a perspective view of a fuse mounting or block disassociated from the racks.

Referring now to the drawings wherein like numerals have been employed to designate similar parts throughout various figures,

it will be observed that F 1 discloses a' panel denoted generally by the numeral 10 which isadapted to be vertically positioned within a telephone exchange and which comprises a plurality of parallel members or racks 11 horizontally disposed between and secured at their ends to vertical posts 13. These racks 11 comprise a channel like frame 1 1 which is provided with an elongated openin 15 (Figs. 1 and extending longitudinally thereof. Carried by and extending along the lower flange portion of the frame 14 is a conductor bar 17 (Fig. which will hereinafter be designated as the ground bar and extending in parallelism with this bar 17 along the upper flange portion of the frame 1a is another conductor or battery bar 18 which is secured in position by means of screws 19 and insulated from the frame 14 by a strip of suitable insulating material'Ql. Equally spaced along the upper surface of the ground bar 17, and extending beyond the rearward edge thereof are a plurality of terminal posts 22 which supply the ground terminals for telephone switchboard circuits or the like (not shown). Positioned above these terminal posts are companion terminal posts 23 which are secured to an elongated insulating member 25 and whicn supply battery terminals for the above mentioned switchboard c' cuits. The terminal posts 23 are formed with a spring portion 26 and are secured to the insulating member 25 by means of screws 27. k

A fuse mounting or block 25) (Fig. 4) is adapted to be inserted within the frame opening 15 between the battery bar 18 and the spring portion 26 of the terminal post 23 (Fig. 3) and includes an insulating block 30. The lower surface of the block 30 is provided with a recess 31 and the forward surface of the block is provided with a vertical recess 32 which terminates at its lower endwithin the recess 31. Terminal members or contact springs 33 and 34k extend iii along the upper and lower surfaces, respectively, of the block and are bent over the rear edges of the block and secured thereto by means of screws (Fig. 3). The forward end of the contact spring 34 is connected by means of solder or the like with the lower end of afuse wire 37 which'i's vertically positioned or lodged within the recess 32 and suitably secured at its upper end to the forward extremity ofthe contact spring,

33. By the provisionof the vertical recess 32, fuse wires may readily be positioned between the springs and the fusesl are readilyaccessible for purposes of repair or replacement. The tension in theforward portion of the spring 33 is such that unless the spring is held in its lowermost position against the upper surface of the bloclrf30, it will normally' assume the upwardly inclined position shown by dot and dash lines (Figs. 3 and 4). The forward end of the contact spring 33 {is bent downwardly to present an indicator'portion' 38 and when the fuse 37 is connected between the springs 33 and 34, it'will tend to oppose the upward movement of the'spring 33 and the indicator portion 38 thereof will be retained in'itslowermost position' adjacent the forward end surface of the block 30. A pair of lugs 39 are formed at each side of the spring 33 and extend v upwar'dlyjtherefrom, and serve to determine the position of the fuse block 29 when it is carried into association with thejraclr 11as will later'be' more" fully described. 7

These fuse blocks '29 are adapted for association with racks 11 as' clearly shown in Fig. 3. The fuseblocks are'inserted from the forward side of one of the racks 11 through the? elongated opening 15 and the recess'31 of the insulated block 30 provides a guide for the'sp'ring 26 of the terminal post'23. This spring 26, uponthe insertion of the fuse block 29, yieldingly engages the contact spring 34 and causes the upper surface of the contact spring33 positively to engage-the lower. surface of the battery bar 7 18. The'upwardly extending lugs 39 on the springs 33 serve" to limit the distance to which the fuse block maybe inserted by engaging the forward surface of the battery bar 18 and the fuse block thus positioned is yieldingly, yet securely, positioned within the rack 11. i

The battery bar 18 (Fig. 3) iselectrically connected with one terminal of a battery 41, the opposite terminal of the battery being connected to ground andit will be understood that the insertion of a fuse block 29 will electrically connect the battery bar 18 with the terminal post 23through the contact spring 33, the fusewire 37 and the contact spring 34. WVith a suitable telephone switchboard signalling orv other type of electrical circuit (not shown) connected across the terminal posts 22 and 23 the circuit may betraced from ground to one terminal of the battery 41, from the opposite terminal of the battery to the battery bar 18, the contact spring 33, the fuse wire 37, the contact spring 34, the terminal post 23, through the circuit (not shown), the terminal post 22 'and th'ence to ground. Upon the parting of the fuse wire 37 caused by an abnormal current flow in the circuit just described, the forward end of the contact spring 33 will be released and will fly upwardly into contact with a conductor or alarm lea-r42 which is secured to and insulated from the forward surface of the frame 14; n1 sodoing the indicator portion 38 of the spring 33 is moved upwardly with respect' to the insulating block '30 and this visible changein' position serves to'apprise-an attendant of the blown" fuse. The alarm bar 42 is electrically connected with one terminal of a signallamp 43, the other terminal thereof being connected to ground through an alarm bell 45. The contacting of the spring 33 with the alarm bar 42 closes the circuit including the battery 41, the battery bar 18, the lamp 43 and'the alarm bell 45.

From the disclosure in Fig. 1 it will be'apparentthat when one of the indicator portions 38 of the fuse blocks 29 is carried upwardly to its changed position with respect to the insulating block upon which it is mounted and with respect to the other aligned indicators supported in the rackan attendant can very easily'identify'the fuseblock to be replaced. The alarm bars 42 are connected with acommon conductor 46 (Figs. land 2) by means of a conductor 48 and the ground bars'17 are connected with acommon conductor 47 through a conductor 50. Likewise each alarm bar 42 is connected through its respective lamp 43 to a common conductor 49 which is connectedto ground through the alarm bell 45. By having this circuit arrangement the blowing of any one of the fuses supported'in any one of the racks which comprise the entire panel 10 will cause the alarm bell 45 to sound and will cause the signal lamp 43 corresponding to the rack in which the blown fuse "is carried to be energized. The

compactconstruct-ion of the apparatus and the comparative ease with which blown fuses may be detected and subsequently replaced greatly facilitates the handling of electrical circuits and thelike in telephone exchanges.

Although the invention has been described rack, a fuse block comprising an insulated mounting, contact springs mounted upon the upper and lower surfaces thereof and a fuse wire connecting the contact springs, the fuse block being movable for manualinsertion between the fixed and resilient conductors in the rack.

2. In protective apparatus, an insulating fuse mounting having a recessed lower edge, terminal members carried thereby, one member being movaole with respect to the mounting and one being mounted within the recessed lower edge thereof, a fuse element electrically connecting the terminal members, and contact members one of which yieldingly engages one of the terminal members within the recessed edge of the mounting to position the mounting between the contact members, the insulating mounting and parts carried thereby eing movable as a unit between the contact members.

3. In protective apparatus for electrical circuits, a mounting plate having therein an elongated opening, a plurality of resilient contact members mounted in the opening, a plurality of rigid contact members mounted in the opening, and a plurality of fuse blocks removably positioned between the rigid and the resilient contact members.

at. In protective apparatus for electrical circuits, a rectangular block of insulating material having recessed portions on the front and bottom thereof, a resilient terminal member on the top of said block, a rigid terminal member on the bottom of said block mounted in the recessed portion on the bottom thereof, and a fuse element electrically connecting the terminal members and mounted in the recessed portion on the front of the block.

5. In protective apparatus for electrical circuits, a mounting plate having therein an elongated opening, a plurality of resilient and rigid contact members mounted in the opening, the resilient members mounted at the bottom edge and the rigid members mounted at the top edge of the opening, a plurality of fuse blocks having recessed portions on the front and bottom thereof, resilient terminal members on the top of said blocks, rigid terminal members on the bottom of said blocks mounted in the recessed portion on the bottom thereof, and fuse elements electrically connecting the terminal members and mounted in the recessed portion on the front of the block, each of the plurality of rectangular blocks and the parts carried thereby being removably positioned between the resilient and rigid contact members.

6. In a protective device, an insulating block, a pair of parallel members mounted on opposite faces of the block and having a terminal portion adapted to be slidably inserted between companion terminals of an electrical conductor and projecting portions integral with the terminal portions, one of the members being of resilient material and the projecting portion thereof having an initial tension tending to move it away from the projecting portion of the other member, and a fusible member normally holding the projecting portion of the resilient member in parallelism with that of the other member. 7. In a protective device, an insulating block, a pair of members mounted on opposite faces of the block and each having a terminal portion and a free end, a fusible member connecting the free ends at one end of the block, one of the members being of resilient material and the free end thereof having an initial tension tending to move itself away from the free end of the other member, a pair of spaced terminals adapted to contact with the terminal portions of the members and another terminal positioned to be engaged by the free end of the resilient member upon the fusing of the fusible member.

In witness whereof, I hereunto subscribe my name this 16th day of September A. D.,

CLYDE LEIGH WETZEL. 

